package com.leetcode.demo21;

class ListNode {
    int val;
    ListNode next;
    ListNode(int x) { val = x; }
}

public class Solution {
    /*public ListNode mergeTwoLists(ListNode l1, ListNode l2) {
        ListNode h = new ListNode(0);
        ListNode ans=h;
        while (l1 != null && l2 != null) {
            if (l1.val < l2.val) {
                h.next = l1;
                h = h.next;
                l1 = l1.next;
            } else {
                h.next = l2;
                h = h.next;
                l2 = l2.next;
            }
        }
        if(l1==null){
            h.next=l2;
        }
        if(l2==null){
            h.next=l1;
        }
        return ans.next;
    }*/

    ListNode mergeTwoLists(ListNode l1, ListNode l2) {
        if(l1 == null) return l2;
        if(l2 == null) return l1;

        if(l1.val < l2.val) {
            l1.next = mergeTwoLists(l1.next, l2);
            return l1;
        } else {
            l2.next = mergeTwoLists(l2.next, l1);
            return l2;
        }
    }



}
